The proposed study examines the impact of environmental influences, such as family factors and major life transitions, on the aging of adults with Down syndrome (DS) across a 21-year time span (1988-2009) by collecting additional data from a sample that was studied from 1988 to 2000. The investigators propose to delineate, in Specific Aim 1, the association of characteristics of the prior family environment (1988-2000) on later life outcomes (2009) of health, functional abilities, and behavior problems among adults with DS; in Specific Aim 2, the prevalence, antecedents, and consequences of major life transitions as experienced by adults with DS over a 21-year period (from 1988-2009), and in Specific Aim 3, the implementation and impact of future planning for aging adults with DS. Given that individuals with DS can now enjoy substantially longer life expectancies as compared to a few decades ago, and there is evidence of heterogeneity in aging among adults with DS, there is a need to understand the factors that contribute to this heterogeneity in aging. The proposed study builds from a project of 461 co-residing families of adults with intellectual disability, conducted by Drs. Marsha Seltzer and Marty Krauss (R01AG08768), which included 169 families of adults with DS, of whom 126 are still alive. As a result, the investigators are in a unique position to examine the association of the family environment with the aging of adults with DS. The surviving adults with DS are now age 35-68, and are the focus of this proposed study. Respondents will be recruited from families that previously participated in the study, and will participate in home interviews and complete self-administered measures. The 21-year time span of the proposed study will make it possible to elucidate environmental influences on the functioning of adults with DS in midlife and the early years of old age. NARRATIVE: This project will provide important data over a 21-year time span (1988-2009) regarding the aging of adults with Down syndrome, as well as yielding insights into the impact of environmental influences on their aging. Such data are particularly timely in light of recent initiatives to promote longitudinal research across the lifespan of individuals with Down syndrome, and to understand environmental determinants of functioning in Down syndrome throughout the lifespan.